MOTOROLA M68000 FAMILY Programmer’s Reference Manual (Includes CPU32 Instructions) MOTOROLA INC., 1992 TABLE OF CONTENTS Paragraph Title Page Number Number Section 1 Introduction 1.1 Integer Unit User Programming Model. 1-2 1.1.1 Data Registers (D7 – D0) . 1-2 1.1.2 Address Registers (A7 – A0) . 1-2 1.1.3 Program Counter . 1-3 1.1.4 Condition Code Register . 1-3 1.2 Floating-Point Unit User Programming Model . 1-4 1.2.1 Floating-Point Data Registers (FP7 – FP0) . 1-4 1.2.2 Floating-Point Control Register (FPCR) . 1-5 1.2.2.1 Exception Enable Byte. 1-5 1.2.2.2 Mode Control Byte. 1-5 1.2.3 Floating-Point Status Register (FPSR) . 1-5 1.2.3.1 Floating-Point Condition Code Byte. 1-5 1.2.3.2 Quotient Byte. 1-6 1.2.3.3 Exception Status Byte.. 1-6 1.2.3.4 Accrued Exception Byte. 1-7 1.2.4 Floating-Point Instruction Address Register (FPIAR) . 1-8 1.3 Supervisor Programming Model. 1-8 1.3.1 Address Register 7 (A7) . 1-10 1.3.2 Status Register . 1-10 1.3.3 Vector Base Register (VBR) . 1-11 1.3.4 Alternate Function Code Registers (SFC and DFC) . 1-11 1.3.5 Acu Status Register (MC68EC030 only) . 1-11 1.3.6 Transparent Translation/access Control Registers . 1-12 1.3.6.1 Transparent Translation/access Control Register Fields for the M68030. 1-12 1.3.6.2 Transparent Translation/access Control Register Fields for the M68040. 1-13 1.4 Integer Data Formats . 1-14 1.5 Floating-Point Data Formats . 1-15 1.5.1 Packed Decimal Real Format . 1-15 1.5.2 Binary Floating-Point Formats . 1-16 1.6 Floating-Point Data Types . 1-17 1.6.1 Normalized Numbers. 1-18 1.6.2 Denormalized Numbers. 1-18 1.6.3 Zeros . 1-19 1.6.4 Infinities . 1-19 1.6.5 Not-A-Numbers . 1-19 1.6.6 Data Format and Type Summary . 1-20 1.7 Organization of Data in Registers . 1-25 1.7.1 Organization of Integer Data Formats in Registers . 1-25 MOTOROLA M68000 FAMILY PROGRAMMER’S REFERENCE MANUAL iii TABLE OF CONTENTS (Continued) Paragraph Title Page Number Number 1.7.2 Organization of Integer Data Formats in Memory . 1-27 1.7.3 Organization of Fpu Data Formats in Registers and Memory . 1-30 Section 2 Addressing Capabilities 2.1 Instruction Format . 2-1 2.2 Effective Addressing Modes. 2-4 2.2.1 Data Register Direct Mode . 2-5 2.2.2 Address Register Direct Mode. 2-5 2.2.3 Address Register Indirect Mode . 2-5 2.2.4 Address Register Indirect with Postincrement Mode. 2-6 2.2.5 Address Register Indirect with Predecrement Mode . 2-7 2.2.6 Address Register Indirect with Displacement Mode . 2-8 2.2.7 Address Register Indirect with Index (8-Bit Displacement) Mode . 2-9 2.2.8 Address Register Indirect with Index (Base Displacement) Mode. 2-10 2.2.9 Memory Indirect Postindexed Mode . 2-11 2.2.10 Memory Indirect Preindexed Mode . 2-12 2.2.11 Program Counter Indirect with Displacement Mode . 2-13 2.2.12 Program Counter Indirect with Index (8-Bit Displacement) Mode . 2-14 2.2.13 Program Counter Indirect with Index (Base Displacement) Mode. 2-15 2.2.14 Program Counter Memory Indirect Postindexed Mode . 2-16 2.2.15 Program Counter Memory Indirect Preindexed Mode . 2-17 2.2.16 Absolute Short Addressing Mode . 2-18 2.2.17 Absolute Long Addressing Mode. 2-18 2.2.18 Immediate Data . 2-19 2.3 Effective Addressing Mode Summary . 2-19 2.4 Brief Extension Word Format Compatibility . 2-21 2.5 Full Extension Addressing Modes . 2-22 2.5.1 No Memory Indirect Action Mode . 2-24 2.5.2 Memory Indirect Modes . 2-25 2.5.2.1 Memory Indirect with Preindex. 2-25 2.5.2.2 Memory Indirect with Postindex. 2-26 2.5.2.3 Memory Indirect with Index Suppressed.. 2-27 2.6 Other Data Structures . 2-28 2.6.1 System Stack. 2-28 2.6.2 Queues . 2-29 Section 3 Instruction Set Summary 3.1 Instruction Summary . 3-1 3.1.1 Data Movement Instructions . 3-5 3.1.2 Integer Arithmetic Instructions . 3-6 iv M68000 FAMILY PROGRAMMER’S REFERENCE MANUAL MOTOROLA TABLE OF CONTENTS (Continued) Paragraph Title Page Number Number 3.1.3 Logical Instructions . 3-8 3.1.4 Shift and Rotate Instructions . 3-8 3.1.5 Bit Manipulation Instructions . 3-10 3.1.6 Bit Field Instructions . 3-10 3.1.7 Binary-Coded Decimal Instructions . 3-11 3.1.8 Program Control Instructions. 3-11 3.1.9 System Control Instructions. 3-12 3.1.10 Cache Control Instructions (MC68040) . 3-14 3.1.11 Multiprocessor Instructions . 3-14 3.1.12 Memory Management Unit (MMU) Instructions. 3-15 3.1.13 Floating-Point Arithmetic Instructions . 3-15 3.2 Integer Unit Condition Code Computation . 3-17 3.3 Instruction Examples . 3-20 3.3.1 Using the Cas and Cas2 Instructions . 3-20 3.3.2 Using the Moves Instruction . 3-20 3.3.3 Nested Subroutine Calls . 3-20 3.3.4 Bit Field Instructions . 3-20 3.3.5 Pipeline Synchronization with the Nop Instruction. 3-21 3.4 Floating-Point Instruction Details . 3-21 3.5 Floating-Point Computational Accuracy . 3-23 3.5.1 Intermediate Result . 3-24 3.5.2 Rounding the Result . 3-25 3.6 Floating-Point Postprocessing . 3-27 3.6.1 Underflow, Round, Overflow . 3-28 3.6.2 Conditional Testing . 3-28 3.7 Instruction Descriptions . 3-32 Section 4 Integer Instructions Section 5 Floating Point Instructions Section 6 Supervisor (Privileged) Instructions Section 7 CPU32 Instructions Section 8 Instruction Format Summary 8.1 Instruction Format . 8-1 MOTOROLA M68000 FAMILY PROGRAMMER’S REFERENCE MANUAL v TABLE OF CONTENTS (Continued) Paragraph Title Page Number Number 8.1.1 Coprocessor ID Field. ..